diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index 6719126ea4e23..580ba2cb751ce 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -4160,6 +4160,7 @@ function adjacent_image_link( $prev = true, $size = 'thumbnail', $text = false )
  *                                     or 'objects' to return an array of taxonomy objects.
  *                                     Default is 'names'.
  * @return string[]|WP_Taxonomy[] List of taxonomies or taxonomy names. Empty array on failure.
+ * @phpstan-return ( $output is 'names' ? list<non-falsy-string> : array<non-falsy-string, WP_Taxonomy> )
  */
 function get_attachment_taxonomies( $attachment, $output = 'names' ) {
 	if ( is_int( $attachment ) ) {
@@ -4204,7 +4205,9 @@ function get_attachment_taxonomies( $attachment, $output = 'names' ) {
 	}
 
 	if ( 'names' === $output ) {
-		$taxonomies = array_unique( $taxonomies );
+		/** @var non-falsy-string[] $taxonomies */
+		$unique_taxonomies = array_values( array_unique( $taxonomies ) );
+		$taxonomies        = $unique_taxonomies;
 	}
 
 	return $taxonomies;
@@ -4222,6 +4225,7 @@ function get_attachment_taxonomies( $attachment, $output = 'names' ) {
  * @param string $output Optional. The type of taxonomy output to return. Accepts 'names' or 'objects'.
  *                       Default 'names'.
  * @return string[]|WP_Taxonomy[] Array of names or objects of registered taxonomies for attachments.
+ * @phpstan-return ( $output is 'names' ? list<non-falsy-string> : array<non-falsy-string, WP_Taxonomy> )
  */
 function get_taxonomies_for_attachments( $output = 'names' ) {
 	$taxonomies = array();
diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 49ab472d37184..2ac3b18212c0d 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -1575,6 +1575,7 @@ function get_post_status_object( $post_status ) {
  *                               from the array needs to match; 'and' means all elements must match.
  *                               Default 'and'.
  * @return string[]|stdClass[] A list of post status names or objects.
+ * @phpstan-return ( $output is 'names' ? array<non-falsy-string, non-falsy-string> : array<non-falsy-string, stdClass> )
  */
 function get_post_stati( $args = array(), $output = 'names', $operator = 'and' ) {
 	global $wp_post_statuses;
diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 29317f0a8bf9b..533a725b4707b 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -278,6 +278,7 @@ function create_initial_taxonomies() {
  *                         one element from the array needs to match; 'and' means all elements must match.
  *                         Default 'and'.
  * @return string[]|WP_Taxonomy[] An array of taxonomy names or objects.
+ * @phpstan-return ( $output is 'names' ? array<non-falsy-string, non-falsy-string> : array<non-falsy-string, WP_Taxonomy> )
  */
 function get_taxonomies( $args = array(), $output = 'names', $operator = 'and' ) {
 	global $wp_taxonomies;
@@ -301,12 +302,13 @@ function get_taxonomies( $args = array(), $output = 'names', $operator = 'and' )
  *
  * @since 2.3.0
  *
- * @global WP_Taxonomy[] $wp_taxonomies The registered taxonomies.
+ * @global array<non-falsy-string, WP_Taxonomy> $wp_taxonomies The registered taxonomies.
  *
  * @param string|string[]|WP_Post $object_type Name of the type of taxonomy object, or an object (row from posts).
  * @param string                  $output      Optional. The type of output to return in the array. Accepts either
  *                                             'names' or 'objects'. Default 'names'.
  * @return string[]|WP_Taxonomy[] The names or objects of all taxonomies of `$object_type`.
+ * @phpstan-return ( $output is 'names' ? list<non-falsy-string> : array<non-falsy-string, WP_Taxonomy> )
  */
 function get_object_taxonomies( $object_type, $output = 'names' ) {
 	global $wp_taxonomies;